Introduction
The Demon is a UAV designed by BAE Systems, as part of its “FLAVIIR” project. It has a novel aerodynamic control system which uses engine exhaust and bleed air to provide the aerodynamic forces usually provided by flaps, ailerons and elevators. It has been called the world’s first “flapless” plane. It first flew, from Walney Island, off the coast of Cumbria, UK on 17 September 2010.

Design and development
The unique circulation control system could be employed to reduce the size of the wing on widebody airliners. Its developers hope that the new design could reduce noise, cut fuel and lower maintenance costs. For military fast jets the technology might help to achieve greater stealth.

The so-called “fluidic flight controls” guide air from a rectangular exhaust nozzle over upper and lower Coandă effect surfaces to establish pitch. For roll control, bleed air is blown over a Coanda surface installed on the trailing edge of the wing. By controlling boundary layer conditions, the fluidic controls can also provide greater lift or drag on take-off and landing.

BAE FLAVIIR project
The FLAVIIR project is a 5 year research programme looking at technologies for future unmanned air vehicles (UAV) funded jointly by BAE SYSTEMS and EPSRC.

Managed from Cranfield University and including 9 other University partners, the programme covers all the key aspects of the next generation UAV from an aeronautical point of view. The focus for the research is the “Grand Challenge” laid down by BAE Systems:

To develop technologies for a maintenance free, low cost UAV without conventional control surfaces and without performance penalty over conventional craft.

Alongside the research into individual technologies themselves, the FLAVIIR project will also deliver a flying demonstrator vehicle for these new advances, thus applying the research methodology to the integration phase and providing direct experience and evidence of real performance benefit.

The £6.2M funding has been nominally split into a 3 year research phase followed by a 2 year demonstration phase, although with technology integration being treated as a research topic in its own right this boundary is necessarily blurred.

The technical research has been split into 7 themed areas; Aerodynamics, Control systems, Electromagnetics, Manufacturing, Materials/Structures, Numerical simulation and Integration.